On Tue, Jan 12, 2021 at 03:31:23PM +0000, Jeff Hostetler via GitGitGadget wrote:
> Teach packet_write_gently() to use a stack buffer rather than a static
> buffer when composing the packet line message. This helps get us ready
> for threaded operations.
Sounds like a good goal, but...
> static int packet_write_gently(const int fd_out, const char *buf, size_t size)
> {
> - static char packet_write_buffer[LARGE_PACKET_MAX];
> + char packet_write_buffer[LARGE_PACKET_MAX];
> size_t packet_size;
64k is awfully big for the stack, especially if you are thinking about
having threads. I know we've run into issues around that size before
(though I don't offhand recall whether there was any recursion
involved).
We might need to use thread-local storage here. Heap would also
obviously work, but I don't think we'd want a new allocation per write
(or maybe it wouldn't matter; we're making a syscall, so a malloc() may
not be that big a deal in terms of performance).
-Peff
